Influência do óxido de níquel e da temperatura de sinterização nas propriedades elétricas e na microestrutura de varistores à base de ZnO.

Abstract

In this work the effect of nickel oxide on the electrical properties of the varistor system ZnO. Bi203. C02O3 Mn02 was studied This system was sintered at 1100°C, 1150°C, 1200°C and 1250°C during 1 hour. The electrical characterization was made by measurements of current density versus applied electrical field The microstructural and ceramic phases characterization were made by scanning electronic microscopy and X-ray. The varistor system containing 0,5% mol of Ni203 sintered at 1100°C showed the best electrical properties The electrical properties in all systems sintered at different temperatures were shown to be poorer Poorer electrical properties observed on the other systems is probably due to heterogenic of grain sizes and shapes in the microstructure of the material.